 /*******************************************************************************
  * Copyright (c) 2004, 2007 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.internal.forms.widgets;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.widgets.*;
 import org.eclipse.ui.forms.widgets.ILayoutExtension;

 /**
  * A pagebook is a composite control where only a single control is visible at
  * a time. It is similar to a notebook, but without tabs.
  * <p>
  * This class may be instantiated; it is not intended to be subclassed.
  * </p>
  */
 public class WrappedPageBook extends Composite {
     class PageBookLayout extends Layout implements ILayoutExtension {
         protected Point computeSize(Composite composite, int wHint, int hHint,
                 boolean flushCache) {
             if (wHint != SWT.DEFAULT && hHint != SWT.DEFAULT)
                 return new Point(wHint, hHint);
             Point result = null;
             if (currentPage != null) {
                 result = currentPage.computeSize(wHint, hHint, flushCache);
             } else {
                 result = new Point(0, 0);
             }
             return result;
         }
         protected void layout(Composite composite, boolean flushCache) {
             if (currentPage != null) {
                 currentPage.setBounds(composite.getClientArea());
             }
         }
         /*
          * (non-Javadoc)
          *
          * @see org.eclipse.ui.forms.widgets.ILayoutExtension#computeMaximumWidth(org.eclipse.swt.widgets.Composite,
          * boolean)
          */
         public int computeMaximumWidth(Composite parent, boolean changed) {
             return computeSize(parent, SWT.DEFAULT, SWT.DEFAULT, changed).x;
         }
         /*
          * (non-Javadoc)
          *
          * @see org.eclipse.ui.forms.widgets.ILayoutExtension#computeMinimumWidth(org.eclipse.swt.widgets.Composite,
          * boolean)
          */
         public int computeMinimumWidth(Composite parent, boolean changed) {
             return computeSize(parent, 0, SWT.DEFAULT, changed).x;
         }
     }
     /**
      * The current control; <code>null</code> if none.
      */
     private Control currentPage = null;
     /**
      * Creates a new empty pagebook.
      *
      * @param parent
      * the parent composite
      * @param style
      * the SWT style bits
      */
     public WrappedPageBook(Composite parent, int style) {
         super(parent, style);
         setLayout(new PageBookLayout());
     }
     /**
      * Shows the given page. This method has no effect if the given page is not
      * contained in this pagebook.
      *
      * @param page
      * the page to show
      */
     public void showPage(Control page) {
         if (page == currentPage)
             return;
         if (page.getParent() != this)
             return;
         Control oldPage = currentPage;
         currentPage = page;
         // show new page
 if (page != null) {
             if (!page.isDisposed()) {
                 //page.setVisible(true);
 layout(true);
                 page.setVisible(true);
             }
         }
         // hide old *after* new page has been made visible in order to avoid
 // flashing
 if (oldPage != null && !oldPage.isDisposed())
             oldPage.setVisible(false);
     }
     public Point computeSize(int wHint, int hHint, boolean changed) {
         return ((PageBookLayout) getLayout()).computeSize(this, wHint, hHint,
                 changed);
     }
 }

